Cook Spaghetti According To Package Directions. Meanwhile, In A Small Skillet, Saute Onion And Green Pepper In Butter Until Crisp-Tender. Crumble Sausage Over Vegetables; Add Mushrooms. Cook Over Medium Heat Until Meat Is No Longer Pink; Drain. Stir In The Olives, Italian Seasoning And Salt If Desired. Add Cream; Bring To A Boil. Reduce Heat; Simmer, Uncovered, For 10-12 Minutes Or Until Thickened. Drain Spaghetti; Add Sauce And Toss Gently. Garnish With Parmesan Cheese If Desired.